If I were to start my own fast food business, I would make my food cheap as fuck and deliberately target locations that have:
A sixth form or university campus nearby. Students are a big market.
Nearby pubs or nightclubs. Doesn't have to be a city centre, could be a local high street. The main intent would be to target the late night crowd.
People care about speed, cost and not eating something that will give them food poisoning, not gourmet food. The luxury market is oversaturated and we have anything but the luxury to do that often.
Also, if it's a sufficiently large eat-in location like a diner, maintaining toilet facilities that don't look like they've been vandalized is important too.
They usually aren't happy when I take a shit inside our local food trucks. They keep telling me it's unsanitary but I always insist that a restaurant must allow its patrons fair use of their toilet facilities.
I hate how this society has turned something as deeply emotional as cooking and turned it into a factory farm where people think burgers and hot dogs just magically appear with fairy magic.
Check out how successful Dick’s is in Washington. They have so many locations now. Their first location was Wallingford, Seattle. It’s about a 1 mile walk from the U district, where a lot of the college kids hang out. Now, Dick’s has a location in most major districts of Seattle, mostly around bars, and even outside of Seattle. They are cheap ($2.50 for a cheeseburger) and super fast because they don’t do customizations with a limited menu. Mostly window only walk up pick up, no dine in (except for the one outside the hockey stadium, but it’s standing only).